Cluster is a concept introduced in tsuru-server 1.2 and allows registering
existing clusters of external provisioners in tsuru. Currently, external
clusters can be registered to kubernetes and swarm provisioners.

Clusters can either have a default flag or have multiple assigned pool. tsuru
will use this information to decide which cluster will be used when interacting
with a pool.

When a cluster is registered in tsuru it means that it becomes visible to the
provisioner as a source of information on nodes and units for applications. It
also become available as a possible destination for the creation of the
resources necessary to deploy or scale an application. See provisioners for details on which resources are created for each
provisioner.

To manipulate clusters the client commands tsurucluster-add, tsurucluster-list, tsurucluster-update and tsurucluster-remove can be
used. You can find more information about them in the client documentation.